Metallic Powder Promotes Nitridation Kinetics for Facile Synthesis of (Oxy)Nitride Photocatalysts

Abstract

Nitrogen‐containing semiconductors (including metal nitrides, metal oxynitrides, and nitrogen‐doped metal oxides) have been widely researched for their application in energy conversion and environmental purification because of their unique characteristics; however, their synthesis generally encounters significant challenges owing to sluggish nitridation kinetics. Herein, a metallic‐powder‐assisted nitridation method is developed that effectively promotes the kinetics of nitrogen insertion into oxide precursors and exhibits good generality. By employing metallic powders with low work functions as electronic modulators, a series of oxynitrides (i.e., LnTaON2 (Ln = La, Pr, Nd, Sm, and Gd), Zr2ON2, and LaTiO2N) can be prepared at lower nitridation temperatures and shorter nitridation periods to obtain comparable or even lower defect concentrations compared to those of the conventional thermal nitridation method, leading to superior photocatalytic performance. Moreover, some novel nitrogen‐doped oxides (i.e., SrTiO3−xNy and Y2Zr2O7−xNy) with visible‐light responses can be exploited. As revealed by density functional theory (DFT) calculations, the nitridation kinetics are enhanced via the effective electron transfer from the metallic powder to the oxide precursors, reducing the activation energy of nitrogen insertion. The modified nitridation route developed in this work is an alternative method for preparing (oxy)nitride‐based materials for energy/environment‐related heterogeneous catalysis.

Molten Salt Synthesis of Mg-Doped Ta3N5 Nanoparticles with Optimized Surface Properties for Enhanced Photocatalytic Hydrogen Evolution

“…Most metals or metal oxides have high melting points, and their direct nitridation in a NH 3 atmosphere is a solid–gas reaction; this process is limited by the slow thermodynamics of filling N atoms into the metal lattice . Consequently, most metal nitrides suffer from nitrogen deficiency, and this largely limits their photocatalytic performance.…”

Single phase of perovskite YTaON2 synthesized for photocatalytic water reduction and oxidation under visible-light irradiation

“…The single phase of perovskite YTaON 2 could be obtained at 800 °C by an enhanced nitriding-kinetics method developed by our group (see ESI † for detail). 25,26 Traditional nitriding samples were also prepared for comparison. The X-ray diffraction (XRD) patterns of these directly nitrided samples without Mg assistance are displayed in Fig.…”

“…The different nitriding products in the two different methods are proposed to result from the difference in nitridation kinetics that can be promoted by the Mg powder according to our previous report. 25 The single phase of YTaON 2 was further analyzed with various characterizations, as shown in Fig. 2.…”

“…The different nitriding products in the two different methods are proposed to result from the difference in nitridation kinetics that can be promoted by the Mg powder according to our previous report. 25…”

The multiple roles of rare earth elements in the field of photocatalysis

“…Therefore, future studies should pay more attention to the application mechanism of pure rare earth oxide photocatalysts. 106…”